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Патент USA US2123015

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July 5, 1938.‘
J. w. MARDEN ET AL
2,123,015
_ SEAL FOR DISCHARGE LAMPS
Filed April 1, 1936‘
[L17
INVENTOR
J 14/. MJFDf/V
6'. NE/Ji' F.
ATTORNE
Patented July/'15, 1938
2,123,015
UNITED STATES PATENT OFFICE
2,123,015
SEAL FOR DISCHARGE LAMPS
John Wesley Marden, East Orange, and George
Meister, Newark, N. J., assignors, by mesne as
signments, to Westinghouse Electric and Man
ufacturing Company, East Pittsburgh, Pa... a
corporation of Pennsylvania
Application April 1, 1936, Serial No. 72,048
5 Claims. (Cl. 176-126)
Our present invention relates to seals for elec
?ciency comparatively high currents must be
tric apparatus and particularly electric discharge impressed upon the electrodes which necessitates
apparatus wherein a discharge occurs between
two electrodes in a gaseous atmosphere under
comparatively high pressure. In the prior art
leading-in conductors‘ for the device not only
capable of carrying the necessary currents, but in
various types of seals have been employed where- '
seal so that the high temperatures of operation
of the device will not destroy the seal formed
at the juncture of the leading-in conductors
for the electrodes with the vitreous envelope.
It is accordingly an object of our present in
vention to provide a novel seal for electric devices
in the leading-in ‘conductors for supplying the
electrical energy to the electrodes or ?lament
within the envelope are sealed through the Vitre
10 ous envelope. Moreover the problem of provid
ing a seal such that the vcoemcient of expansion
of the metallic leading-in conductor approxi
particularly of the high pressure type employing
mates that of the vitreous envelope so as to pre-
a gaseous medium wherein the leading in con
vent cracking of the seal with attendant loss of
ductor forms an integral seal with the vitreous
envelope of the device which will not be detri 15
ll the vacuum or gaseous medium has long been
recognized.
mentally aliected by the high temperatures of
The customary construction has been to pro
vide the leading-in conductor with a section of
of the gaseous medium contained within the en
a metal having an analogous co-emcient of ex
20 pansion to that of the vitreous envelope with
the remainder of the leading-in conductor be
ing of a less expensive metal or of a refractory
operation of the device nor by the high pressure
velope.
Another object of our present invention is the 20
provision of a seal for a vitreous envelope or con
tainer wherein the leading in conductor is sealed
metal capable of withstanding high temperatures
to the envelope in such manner as to provide an
due to heating of the electrode or ?lament. How
ever, with such construction that portion of the
temperatures and pressures of operation of the 25
leading-in ‘conductor having the desired, co-ei
integral seal capable of withstanding the high
device and of carrying the requisite electrical
?cient of expansion has limited to a considerable
extent the current carrying capacity of the lead
currents during operation.
ing-in conductor.
provision of a seal for a vitreous envelope or con
,
In instances where the electric discharge de
vice comprises a vitreous envelope provided with
oppositely disposed electrodes between which a
discharge occurs the electrodes are either heated
to a thermionic emission from an exterior source
or the electrodes are thermionically' heated by
the discharge occurring between theeIectrodes
upon the application of electrical energy thereto.
In addition the envelope is usually provided
with a gaseous medium comprising a metallic
vapor, such for example as sodium, cadmium,
mercury or the like at a substantial pressure
ranging from a few millimeters of mercury to
several atmospheres. Moreover as the pressure
of the gaseous medium normally increases with
46 increase of temperature the provision of a suit
able seal for the leading-in conductors presents
an even more momentous problem than is pres
ent with the usual incandescent lamp or electric
device utilizing a vacuum.
50
additional’ such character as to form a perfect,
We have previously shown and described in our
copending application Serial No. 49,448, ?led
November 13,v 1935, that the maximum e?‘lciency
of a high pressure mercury vapor lamp is de
pendent on the maximum wattage per centimeter
55 of arc length. _In order to obtain maximum ef
Another object of our present invention is the
tainer wherein the leading in conductor is pro 30
vided with a portion formed of thin metal hav~
ing a high melting point and due to its cross
sectional area forms an integral seal with the en
velope without the necessity of the seal forming
portion being of the same coef?cient of expan
sion as that of the envelope.
Still further objects of our present invention
will become readily apparentto those skilled in
the art by reference to the accompanying draw 40
ing wherein,
Figure l is a fragmentary view in cross-section
of an electric discharge device particularly of
the high pressure metal vapor type provided with
a seal constructed in accordance with our pres
45
ent invention.
Figure 2 is an enlarged cross-sectional view
taken on the line 11-11 of Fig. 1.
Figure 3 is a perspective view on an enlarged
scale of a seal for electric discharge devices 0011- _
structed in accordance with our present inven
tion, and
Figure 4 is an elevational view partly in cross
section showing the manner of constructing an
electric discharge device of the metal vapor type 55
2
8,198,015 t
employing seals in accordance with the teach
ings of our present invention.
,
Referring now to the drawing in detail we have
shown in Fig. l a vitreous envelope I constructed
of hard glass, silica, or the like, but in instances
with its respective electrode and ‘seal forming por->
, tion is inserted into the chamber lI‘and moved I
downwardly of the chamber II until the upper
electrode is positioned the desired distance from
the lower electrode. The open end of the cham- -
where the device is of the metallic vapor type ' ber II is then sealed as shown at II to thus hold
the upper electrode and leading-in conductor in
which is subjectable to high temperatures of op
eration it is preferable to construct the container
or envelope I of quartz due to its high melting
10 point. The envelope I is provided with a tubular
extension I formed thereon during the sealing
in process and embedded in the tubular portion
is a leading-in conductor forming an integral
seal with the tubular extension portion of the vit
II reous container or envelope. The construction of
this leading-in conductor may be better appre
ciated by particular reference to Fig. 3 wherein
the leading-in conductor comprises a substan~
tially cylindrical member 'I. This member may
.
,
The vacuum pump (not shown) which is con
nected to the chamber II is then operated to 10
evacuate the envelope I and the lower portion of
the envelope I is suitably heated by flames II
until the envelope attains a suitable fusing tem
perature and at the same timethe vitreous core
II- of the leading in conductor is also heated to II
the fusion pointresulting in complete fusion of
the core II with the envelope I both above and
below the cylindrical metallic foil portion ‘I and
also fusion of the core I l and envelope I occurs
be formed of any suitable thin metal, such as
through the longitudinal opening I provided in
tungsten, tantalum, but preferably molybdenum
the cylindrical metallic foil section ‘I until com
plete fusion of the core II and envelope I results.
thus completely embedding the leading-in con
foil of about 1 mil thickness. This metal is
formed into the con?guration of a cylinder by
rolling and joining the overlapping ends and se
curing the same in any suitable manner, such as
by welding I.
The cylindrical metallic foil member ‘I is pro
vided with a longitudinal slot 9 for a purpose to
be hereinafter more fully described and connected
to this member 1 in any suitable manner, such
as by welding, is an electrode III of suitable re
fractory metal, such as tungsten, which may be
provided with an additional refractory metal layer
of coiled tungsten I2 with this portion being sub
jected to the discharge between the oppositely
disposed electrodes during operation of the device.
Also connected to the cylindrical metallic foil
portion is a rod like portion or wire II which may
be formed of substantially U-shaped configura
40 tion having its ends secured as by welding to the
metallic foil portion with the remaining portion
of the wire II joined in a similar manner to the
base of the U-shaped portion and constituting
that portion of the leading in conductor adapted
to be disposed exteriorly of the container or en
velope I asshown more clearly in Fig. 1. Prior
to connection of the exteriorly disposed portion
II of the leading in conductor a core of vitreous
material ll of the same composition as that of the
vitreous envelope I is inserted in the cylindrical
metallic foil portion ‘I of the leading in conductor
thus conditioning the same for sealing in to the
envelope ‘of the discharge device. This latter
step may be accomplished in any suitable manner,
but we find it expedient to employ the method and
apparatus shown more particularly in Fig. 4.
As the spacing between the electrodes of a dis
charge lamp of the metal vapor type is an essen—
tial factor in its efficiency of operation we first
join the envelope I to a suitable vitreous chamber
II and provide the opposite end of the envelope
with a tubular member II having an elbow or the
like II.
The lower leading-in conductor as viewed from
65 Fig. 4, together with its electrode and seal form
ing portion, as shown more particularly in Fig. 3,
is then inserted into the chamber II while its
upperend is open and such leading-in conductor
slid downwardly of the chamber II and envelope
70 I until the extremity of the leading-in conductor
ductOr and particularly the cylindrical metallic
foil portion ‘I in the tubular portion I formed on
the envelope I'during the fusion to form a com
plete integral seal with the envelope.
After the desired degree of evacuation of the
envelope I is obtained and the appropriate gas
eous medium or vapor forming metal is intro
duced into the envelope I the ?ames I! are moved
adjacent the upper seal forming portion where
the same operation is performed to form the up
per integral seal between the envelope I and the
leading-in conductor particularly the cylindrical
metallic foil portion 1. The envelope I and por
tions II ofv the leading-in conductor are then
severed from the chamber II and tubular mem
ber II thus completing the device.
It thus becomes obvious to those skilled in the
art that we have provided a leading-in conductor
particularly adaptable to electric discharge de
vices subjectable to extremely high temperatures
and pressures during operation wherein the lead
ing-in conductor forms an integral‘seal with the
vitreous envelope. Moreover, the seal forming
portion being of comparatively thin metal or
foil facilitates the radiation of heat which is gen
erated by the resistivity thereof to the passage of
the electric current thus obviating possibilities
of cracking of the seal. While preferably the
seal is formed of a metal having a coefllcient of
expansion simulating that of the vitreous en
velope it need not necessarily have such precise
coemcient of expansion due to its being of com
paratively thin cross section. In addition the
area of cross-section of the cylindrical metallic
foil portion of the leading-in conductor is such
that the requisite electrical current can be readily
supplied to the electrodes without danger of over
heating.
Although we have shown and described one
specific embodiment of our invention we do not
desire to be limited thereto as various other mod
i?cations of the same may be made without de
parting from the spirit and scope of the invention
as set forth in the appended claims.
What is claimed:
rately positioning the leading in conductor and
1. The combination of a vitreous container, a
conductor fused to a portion of said container 70
comprising a cylinder of metal foil, a leading
in conductor secured to the wall of said cylinder
electrode within the lower portion of the enve
and extending exteriorly of said container, and
rests against the shoulder portion I‘I thus accu
lope I preparatory to the sealing in operation.
II
this desired position.
Next the upper leading in conductor together
an electrode within said container ‘having its
ends connected to the periphery of said cylin- "
2,123,015
drical conductor and extending a substantial
distance on the surface thereof in the direction
of the longitudinal axis of said cylinder to form
a support for said electrode.
2. The combination of a discharge device pro
vided with an envelope of vitreous material, lead
ing-in conductors comprising substantially cy
lindrical members formed of‘metal foil having
their interior and exterior surface fused to said
10 envelope to form a seal, leading-in conductors
secured to the wall of each of said cylindrical
members and extending exteriorly of said en
velope, and electrodes within said envelope be
tween which a discharge occurs when supplied
15 with electrical energy and subjectable to ex
3
discharge device having a vitreous envelope com
prising a substantially cylindrical member of
metal foil having a core of vitreous material
readily fusible with the envelope of said discharge
device to form an integral vacuum tight seal, an
electrode having its ends connected to the pe
riphery of said cylindrical member and extending
a substantial distance on the outer surface in
the direction of the longitudinal axis of said
cylindrical member, and a wire having a bi 10
furcated end portion connected to the periphery
of said cylindrical member and extending a sub
stantial distance on the outer surface in the di- -
rection of the longitudinal axis of said cylindrical
member, and a wire having a bifurcated end por
15
tion connected to the periphery of said cylin
drical member and extending a substantial dis
tance on the outer surface thereof and extending
tending a substantial distance on the surface exteriorly of the envelope of said discharge de
20 thereof in the direction of the longitudinal axis vice.
20
of said cylinder to form a support for each of said
5. A current conducting seal for an electric
electrodes directly from said seals.
discharge device having a vitreous envelope com
3. The combination of a discharge device pro
prising a substantially cylindrical member of
vided with an elongated envelope of vitreous metal foil having a longitudinal slot therein and
25 material, a leading-in‘ conductor disposed at op
provided with a core of vitreous material of the 25
posite ends of said elongated envelope compris
same composition as the envelope of said dis
ing substantially a cylindrical member formed charge device and readily fusible with the lat
of metal foil having a core of the same vitreous ter to entirely surround the cylindrical member
material as said envelope to form a fused seal in
and form an integral vacuum tight seal, an elec
30 tegral with the latter, a leading-in-conductor
trode having its ends connected to the periphery
secured to the wall of said cylindrical member of said cylindrical member and extending a sub 30
and extending exteriorly of said envelope, and stantial distance on the outer surface in the di
an electrode disposed at each end of said en
rection of the longitudinal axis of said cylindrical
tremely high temperatures, each of said elec
trodes having its ends connected to the periphery
of the respective cylindrical member and ex
velope between which a discharge occurs and
35
subjectable to extremely high temperatures, and
each of said electrodes having their ends con
nected to the periphery of the respective cylin
drical member and extending a substantial dis
tance 0n the outer surface thereof in the direc
40 tion of the longitudinal axis of said cylindrical
member to form a support for each of said elec
trodes directly from said seal.
4. A current conducting seal for an electric
member, and a wire having a bifurcated end por
tion connected to the periphery of_said cylindrical
member and extending a substantial distance on
the outer surface thereof, and the remaining
portion of said Wire being coaxially disposed
relative to the longitudinal axis of said cylin
drical member and extending exteriorly of the 40
envelope of said device.
JOHN WESLEY MARDEN.
GEORGE MEIS'I'ER.
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